Over the past several years, there have been many developments in mobile devices, often leading to an individual carrying several mobile devices for different functions and also carrying several accessory devices, such as earphones, earphone/microphone combinations, keyboards, portable printers and the like, for those mobile devices. Conventionally, the various mobile devices and accessory devices have communicated with each other and also between mobile devices using wired connections. More recently, wireless connections have become available, initially by using infrared, and more recently by using Bluetooth™ or IEEE wireless standards. The Bluetooth™ standard has been specifically developed with regard to personal area networks (PAN). A personal area network is designed to allow mobile devices and accessories that are within a predetermined range of each other to form wireless connections.
Depending on the type of data exchange between a mobile device and an accessory device or between mobile devices, it can be very important to have a secure wireless connection. There are many security protocols that can be used in wireless connections, each having various features, including the length of an encryption key or key generator (both referred to as an encryption key herein), which is related to the amount of the computational power required to break the encryption. Generally speaking, greater security is provided by having a longer encryption key. In most security protocols it is necessary to first exchange the encryption key that will be used in the secure communications in a non-encrypted manner. The exchange of the encryption key thus becomes a potential weak point in the security system.
As a particular example using the Bluetooth™ security protocol, a personal identification number (PIN code) is used to generate encryption keys. The PIN code is an alpha-numeric string that can be, for example, generated by one device and then entered by a user onto another device. Conventionally, in establishing a Bluetooth™ connection, a mobile device first detects accessory devices or other mobile devices within the Bluetooth™ range, then allows a user to select one of the other devices as a connection target. The mobile device then notifies the user of a PIN code that the user enters on the accessory device to establish secure wireless communications.
The use of the PIN code (i.e. an encryption key) allows the creation of an encrypted wireless connection between devices to protect against viruses and hackers and maintain privacy. The use of the PIN code can also ensure that the mobile device will only be receiving a particular type of input from the particular accessory device to which the mobile device is intended to be connected.
The need to enter a PIN code in order to establish secure communications can be problematic because it conventionally requires that one or both of the devices to be connected have some method of displaying the PIN code and/or some form of data entry capability such as a keyboard, keypad, stylus or the like.
A further difficulty with the use of a PIN code in this manner is that, in order to achieve the appropriate level of security, the PIN code needs to have a significant number of digits, and preferably, an assortment of different types of digits so that the PIN code cannot be readily ascertained. This makes it more difficult for the user to accurately transfer the PIN code between devices. There is also the possibility that security could be compromised if the PIN code is observed while being entered on the accessory device.
As such, there is a need for an improved method of transferring/exchanging an encryption key between computing devices.